Starting build up - questions?

[Fredduck]

I'm about to finalize by parts list for my cummins build up on my 88 YJ and wanted to bounce my idea off some of you to see if I missed any thing. :?:
We'll start with the engine, it'a a 3.9 cummins turbo diesel. Its rated at 120 HP and 250-300 FT/LB of torque. Whats nice about this engine is the size and availablity of parts, injectors and other parts are the same as the 5.9 but without all the weight.  :shock: It came with a chevy automatic transmission adaptor. I'm attaching a 700R4 with a diesel convertor for bottom end grunt.  
For a transfercase I'm going with a NP241-C. It will need a super short SYE so I won't have to attach the transfercase to the rear diff. I will order JB Conversions Super short kit.
For Diffs I'm going to go with a Ford 9 inch in the rear and a Dana 44 in the front both geared at 4.10, out of a Bronco. I plan on a spring over when I install them so the lift for the 33's won't be an issue.

Once I get the drive line mocked up I can measure for drive shafts and exhaust. I know I will have to get additional springs in the front to accomadate an addition 300 LBs of weight(engine and winch).

Any comments or concerns will be gladly accepted. Any good leads on parts that I may have overlooked please PM me.
THX
The Duck

[Dragonmaster]

I think you've got it all covered other than the massive amount of wiring you're onna have to do.

Good luck and don't forget to post results.

[dunl]

It will need a super short SYE so I won't have to attach the transfercase to the rear diff.

LMAO. :lol:

[BlackYJ]

Once I get the drive line mocked up I can measure for drive shafts and exhaust. I know I will have to get additional springs in the front to accomadate an addition 300 LBs of weight(engine and winch).

If you are going to the trouble of swapping in that engine and going SOA, then I would seriously check out Alcan Springs, http://www.alcanspring.com/.  They custom make your springs and I have heard they are about the only SOA spring that stands up and doesn't sag.  I have a set of their SUA springs and the guy told me I should get 6-7 years out of the springs.

[Fredduck]

The wiring really isn't  much of an issue: the lock up of the converter will be handled by a thumb button on the gear shift A buddy of mine has done this already with a late 70's chevy. The diesel only needs a stop button, everything else is there. And the fact 90% of the wiring doesn't work already :lol: . I will look into the Alcans, thats a good Idea :idea: . I'm also going to go with electric fans, 1 pushing and 1 pulling. That should free up some space forward so I can gain some lenght on the rear of the transfer case. I still have to find an intercooler about the same width as the YJ rad, it will go across the top infront of the rad with an oil and a trans cooler rounding out the bottom.

[cLAY]

Think about a body lift. The cummins is a TALL motor(all stroke). There could be some issues with front axle clearance with the oil pan on flex. Body lift may allow for the motor to be mounted higher in the frame allowing for more suspension flex.

[Fredduck]

Thanks good tip. I have to pull the body off to fab new mounts for the engine, trans and transfer case so that wont be too much of an effort. When I get the cummins sitting where I want we're going to drop the body on and check clearances before tighnening bolts. The engne is a rear sump simular to a SBC (just a little fatter) . My YJ has a bit of a lift on it now but after the drive train is sitting in the frame the suspension has to be revisited.

[hps4evr]

you say dana44 and ford 9inch, from what bronco year. ive got full width dana44 and 9inch from a 78ish ford truck and it has the mounts for the front coil setup right on the front axle housing. may be a good swap to run coils/coilovers. keep the rear as spring over. im thinkin of using a spring over with rancho wagoneer springs. little bit longer wheel base. gain rear driveshaft length. the body lift is a good idea as well. if all you need is a 1inch BL then look at the daystar 1inch kit. replaces the factory body mounts with poly bushings that are 1inch taller then stock. im almost certain your t/case drop is on the same size as the diffs. but im just mentioning it to be sure.oh and watch the front drivshaft clearance at the trans pan. heard it could be an issue. keep up with the updates, diesel swaps are the shizzle;)

[Fredduck]

I say ford 9 inch and dana 44, that is if I can get the guy that owns them now to pick up the phone :roll: . They are out of a 79 bronco, the reason I thought I would go with these is they are only about 5 inchs wider total than the stock YJ. so I can kick the wheels out a little bit to add some stability. I don't think my skill set will allow me to do a front coil suspension set up so for now I'm gonna have to stay with the leaf spring. I'll clean off the original brackets and install spring saddles. This is my first jeep build so I'm gonna have to keep the suspension as simple as I can. Installing the cummins and fixing the electrical will keep me busy enough

[cLAY]

The pan maybe not much deeper but the block on the cummins will be a fair bit taller than a chev, I'm guessing you may even need to tilt the driveline a bit to get the tranny down to have decent shaft angles and keep the tranny in the tunnel. ie you'll have to mount the engine high in the frame to clear the diff with the front tilted a bit up so that the output of the t-case will be lower. This could screw up the front shaft though.

[Fredduck]

I'll be spending a few hours with hydraulic jacks and timbers getting things lined up

[Fredduck]

I found my Dana 44 and Ford 9 inch, I have questions and perhaps issues.
The 9 inch doesn't look like it is going to be an issue beside moving spring perches. The Dana might be an issue and I need some "I luv cup cakes"istance before dropping my cash.
The Dana is out of a 79 Bronco, they had coils. It looks like where I am going to mount spring perches for my leafs is a diamond shaped castings for the radius arms. WMS TO WMS is 66 inches
My question is has anybody come across this and what did you do about it?
Next issue; I was planning a spring over conversion, but it looks like I'm going to have spring interferance with the steering linkage. The nice thing is that it looks like a high steer set up. HELP :shock:  :shock: The guy is going to give me all the spring buckets and brackets from the Bronco but I know I'm not talented enough to convert the YJ to a front coil :cry:

[hps4evr]

ive seen a couple yj;s with the leaf sprung over this axle. they seem to avoid the spot you are talkin about. its the spot for the radius arms to bolt to the front axle on the oem ford set-up. i know there are a couple guys on this website that have done this. if not, check out pirate4x4, odds are someone there has done this. im doing a similar swap eventually on my yj. but havent decided on leaf spring under the axle or radius arms and coil-overs. money is always an issue but consider bot h options and see which one is more work. grinding the axle for leafsprings and making the steering fit, or using the coils and building coilbuckets on the jeep frame and adding radius arm brackets... to me the coild look way easier. steering wont be as much an issue after either. all i can say is research the subject and call a few people that have done this. look at their jeeps.
good luck man!!!

[Bnine]

It depends on the year of hp44.  It either started in, or after 79, but the later models had the radius arm mounts casted into them, making them hard to work with.

You can confirm the right year over on pirate, there will be someone quick to answer with the right years.

The only thing I would recommend in your build is more axle. An older 14 bolt rear with the right d60 hubs is the same width as that 9, and about 4 times as strong.

On the front, I would watch ebay for a 78 or 79 ford hp dana 60.

If you plan to wheel that kind of  weight and torque, it will be rough on those axles.

[Fredduck]

THX HPS and B9 good food for thought. I know I have to change from the stock set up just on torque alone.
I think I'm going to go with the 44 and 9 inch for now, I haven't done any killer wheeling to speak of. If I do manage to break something then we'll have to go stronger